Nowadays, operators of these electric vehicles require the same bus to be able to be supplied with electrical power from the first catenary and, alternately, from a second catenary which supplies a second voltage which is lower than the first voltage. To this end, the main transformer is equipped at the secondary winding with a second connection terminal which corresponds to a second winding ratio of the main transformer greater than the first winding ratio.
In this context, the invention proposes a method which is capable of supplying the DC supply bus of the electric vehicle with electrical power from the first catenary and, alternately, from the second catenary.